Why can't I get my iphone to read my text to me?

My husband and I have the same phone the iphone4 his will read his text to him if he touches it it gives him the option to copy or read. Mine only gives me the copy option how can I make mine read to me too?

Open the Settings app on your home screen.
Tap the General tab.
Scroll down and tap the Accessibility tab.
Tap the Speak Selection option (it should be set to off, currently).
Tap the toggle switch to turn it on. You can also adjust the rate of speech as well. It's worth noting, however, that the default is already pretty fast. If anything, you might want to slow it down.